When a well is drilled into a geological formation, logging tools are used to determine a variety of characteristics of the well. Some logging tools may determine characteristics of the surrounding rock formation. Other logging tools may measure characteristics of fluids and/or other annular fill material present in the well. Still other logging tools may determine when cement, resin, and/or the like has been properly installed in the well to achieve zonal isolation.
In certain cases, a logging tool may be configured to detect the presence and/or location of one or more annular fill materials behind the casing of a well. To this end, cement may have distinguishable acoustic properties that may facilitate its detection by acoustic logging tools. However, certain annular fill material, such as resin, may be associated with acoustic properties that have relatively low contrast with other annular fill material. As such, using acoustic measurements to distinguish between the resin and other annular fill materials may be challenging.